I know they can be emptied at furnaces, but they can't be emptied anywhere else. When you are in your bank, there is an option to empty the ore box, but it doesn't actually do anything. I would also appreciate the ability to empty ore boxes from bank deposit boxes. If you're just wanting to mine ores to sell, having to empty all of your ores into the metal bank, then withdraw them and go to the nearest bank/ge seems unnecessary when it could be possible to just put them from the ore box into the bank/deposit box.
You can empty your ore boxes at furnaces, anvils, forges, as intended.
The 'empty' option of the ore boxes whilst in the bank interface isn't functioning for the moment, but the Jmods are aware of it. A workaround would be depositing your ore box at the bank; it will empty it in the process.